1. Field of the Invention
The present invention relates to an exposure apparatus of an optical disk master, and more particularly, to an exposure apparatus and method of an optical disk master using a deflector.
2. Description of the Related Art
FIG. 2 shows an example of a conventional exposure apparatus 200 of an optical disk master. In FIG. 2, reference numeral 201 denotes a laser source; 202, an EO modulator that eliminates low-frequency noise of the laser or performs power control; 203, an AO modulator that performs modulation using an information signal; 204, a lens system that focuses a laser beam into a crystal of the AO modulator; 205, an EO deflector; 206, a beam expander that focuses the laser beam and enlarges it to a desired beam diameter; 207, a polarizing beam splitter (PBS); 208, a ¼ wavelength plate; 220, a resist-coated optical disk master (herein resist master); 209, a head that focuses the laser beam on the resist master 220; 210, a turn table that turns the resist master 220; 211, a CCD camera that monitors the laser beam reflected from the resist master 220; 212, a lens that focuses the laser beam onto the CCD camera.
The laser beam output from the laser source 201 enters the EO modulator 202, called a “noise eater”, to reduce laser noise input to the EO modulator 202 and adjust the laser beam to desired intensity. The laser beam that has passed through the noise eater enters the AO modulator 203 that performs intensity modulation using an information signal. Since the modulation speed of the AO modulator 203 depends on the beam diameter in the crystal; the greater the degree of focusing of the beam, the faster the modulation becomes, the lens system 204 is arranged in such a way as to come into focus in the crystal of the AO modulator 203. Primary diffracted light output from the AO modulator 203 is input to the EO deflector 205 that performs deflection modulation. The laser beam output from the deflector 205 is enlarged in the beam diameter by the beam expander 206 and then focused onto the resist master 220 by the head 209 to expose and record the information signal.